Typically, a discharge amount of tap water used in each home varies depending on the position of a faucet, even when using water pipes of the same dimension, and the water pressure and the discharge amount flowing through the water pipe vary due to the position of a water tank and a difference in level between the water tank and each faucet. Further, in the case of an aging water pipe, the discharge amount varies with the presence of foreign matter such as internal scale or the like.
Since the aforementioned water pressure is proportional to the dimensions of the water pipe and the flow rate of the water within the pipe, a faucet device fed by a weak water pressure will discharge less water than a faucet fed by a strong water pressure in the same amount of time.
Accordingly, high-rise buildings have a problem in that there is a need to accept a loss generated by the waste of some of the discharge amount due to the unnecessarily high water pressure.
In view of such a problem, a flow control device which measures the water pressure of the water pipe and reduces the cross-sectional area of the water pipe so that the discharge amount matches a reference value is disclosed. Thus, since the flow rate is controlled by controlling the area, regardless of the internal water pressure of the water pipe, many types of required flow control devices need to be manufactured depending on the dimension and the water pressure of the water pipe. Currently, since a specific flow control device is mounted after visiting each house to measure the dimensions of the water pipe, the water pressure and the discharge amount, after disassembling the valve, there is a problem in that a lot of labor and time for mounting the flow control device is taken.
Meanwhile, in a water supply device that is commonly used, if a user selects one either the cold water or the hot water, the other is closed. However, if a user tries to obtain the supply of adequate hot water, he controls a controlling lever. At this time, because the water pressure of the cold water is typically higher than the water pressure of the hot water supplied from a boiler, when the cold water and the hot water are mixed, there is a problem in that the cold water flows backward toward the hot water with a weaker water pressure, the fuel cost for producing the hot water increases, and economic efficiency is lowered.
In addition, when using the hot water forced backward by the cold water, there is a need to discharge a certain amount of water. However, because the hot water of an appropriate temperature is supplied, its usage is cumbersome. Also, since the water supplied until the hot water of a suitable temperature arrives is discarded, there is a problem of a wasted water.